Collapsible tap



UNETEB RUDOLPH A. BOEHIVI, OF ERIE, PENNSYLVANIA, ASSIGNOR TO BICKEBT-SHAFER COI/IEANY, OF ERIE, EENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

COLLAPSIBLE TAP.

Specification of Letters Patent.

Patented May e, was.

Application filed November 12, 1920. Serial No. 423,671;

T 0 all whom it may concern Be it known that I, RUDOLPH A. Boni rtr, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Collapsible Taps; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification.

My invention relates to collapsible taps of the type shown in United States Letters Patent No. 1,345,744 issued July 6, 1920, to me upon my application for patent, and assigned to Bickert-Shafcr Company, brie, Pennsylvania.

The object of my invention is to construct a tap which is provided with micrometer adjustment mechanism by which the diameter of the threads can be regulated; also to provide mechanism within the tap body whereby the thread cutters or chasers are caused to recede from the threads by reason of a backward pull exerted upon the shank of the tap mechanism, and the rotative movement of the work piece causing the body of the tap to rotate therewith after the said backward pull of the shank- These and other features of my invention appear hereinafter in the specification and claims, and are illustrated in the accompanying drawings in which Figure 1, is a longitudinal central section of my improved collapsible tap mechanism.

Figure 2, is a central longitudinal section of Fig. 1, with part of the operating mechanism thereof in elevation; i. e. a one-fourth turn with relation to the view in Fig. 1.

Figure is a view in elevation with a portion of the shell thereof broken away, showing one of the driving stops and spring ratchet.

Figure at, is a transverse section on the line l-5 in Fig. 3, looking downward.

Figure 5, is a transverse section on the line l-5 in Fig. 3, looking upward.

in these drawings A indicates the body member of my improved collapsible tap, which is provided on its lower end with radial slots. The body A is cylindrical in contour, and is provided with acylindrical chamber A, in the upper portion thereof, and is also provided with the central opening ja extending from the chamber A longitudinally through the bottom of the/body member A, and communicating with the radial slots in which the chasers B are placed, as is shown and described in said Letters Patent.

In the walls of the central longitudinal opening A I provide longitudinal grooves a which coincide with the central lines of the Chasers B. \Vithin the longitudinal opening A I place a part B having on the lower end thereof inclined radial ribs B which are under-cut on each side thereof; the ribs B entering suitable slots in the inner inclined ends 7) of the chaser-s B; and passing downward through the grooves a, in the central opening A in the body A so that when the chasers B are in place in the lower end of the body A the slots in the inner inclined ends thereof will embrace the under-cut ribs B on the lower end of the member B, so that a longitudinal movement of the member B will cause a radial movement of the chasers B, as described in said patent.

The member B is provided with cams B upon which a shaft B extends; the shaft B and the member B being integral. Upon the shaft B I place a sleeve C which is provided with. cams C and C in its lower and upper edges; the cam G being adapted to co-operate with the cams B in the member B. The sleeve C'is provided with oppositely extending arms C by means of which the sleeve C may be caused to rotate upon the shaft B as hereinafter described.

Upon the shaft B, above the sleeve G, I place a sleeve collar D the lower end of which is provided with cams D which are adapted to co-operate with the cams C on the sleeve C, as hereinafter described; the sleeve collar D being non-rotatably secured upon the shaft B by means of a transverse pin (Z which passes therethrough.

Upon the central members, via ;--B", sleeves C and 13,1 place the shank of my tap, composed of the parts E and E; the part E of the shank being provided with an enlarged portion E which slidably fits within the chamber A of the body A, said enlarged portion E being provided with a slot E which embraces the radial arms of the sleeve C, and upon the lower end of the en larged portion E of the shank E, l secure a ring E by means of screws 6., as shown in Fig. 5.

The ring li is provided with radial notches e for the purpose hereinafter set forth. The upper end of the enlarged portion E of the shank part E forms an annu lar shoulder a, and secured in the radial arms (7 are posts 0, which extend upwardly from the said arms and through openings in said annular shoulcer 6 Above the shank part E I place a collar having; screw threads thereon, which is i dapted to ensage internal threads at the upper end or the chamber A of the body A, and below the screw thread collar F I place an anti-friction bearing ring F and a ring I, which rests upon the posts 0. The collar F is provided with a flange f" which overlaps the exterior oi? the body A at the upper end thereof, and is provided with scale as shown in Fig. 3, whereby a micrometer adjustment of the chasers may be had.

Upon the upper end or the shank part I secure the shank part E by means of the keys G, (see 1) and pins G (see Fig. 2), the keys being for the purpose of preventing rotation between the parts and E, and the pins G", to prevent relative longitudinal movement.

Within the shank part E I place a sprir H the lower end oi? which is secured to the shaft B by means of a pin ii, and the uppe cno oi said spring is secured to a block H by means of a pin it; said block H being longitudinally secured within the shank part E by means of the large headed screw J which engages the annular shoulder 55" with in said shank part E; and it is by means of the screw J that the tension oil the spring H is regulated; a screw li being provided for the purpose of preventing the rotation of the block H by entering one of the series of slots K in the block ll.

In the lower portion of the member provided a cross bar ll the ends of which project into the adjacent rooves o; for the purpose hereinafter set tor T indicates I ll. .u a hand lev r secured in the side of the body A. by means of which the body A be rotated suiticiently to expand the cLa B.

M (see Fig. l) indicates an annular ul der in the body A between the chamber and the central longitudinal opening A". In this annular shoulder M I place upwardly projecting studs M (see Figs. 8 and l) which are adapted to engage the slots 6 in the ring E and are held in such engagement by the action of the spring H which tends to draw the shank part E toward the annular shoulder M.

N indicates a spring pressed ratchet stud which is adapted to be depressed by the ring during the operation of the tap, but

which, when the shank part E and ring E are raised upwardly to disengage the stuu M, continues in engagement or the under surface 01"? the ring E and as the body member revolves upon the shank part laid spring pressed ratchet ll enters one of the slots e in the ring E and stops said rotation; said stopping occurring when the chasers l? have been fully withdrawn from their work.

The spring pressed ratchet bolt N is provided with longitudinal slots in opposite sides thereof, adapted to receive the inner end of the set screw N as shown in'broken lines in Fig. 3, the purpose of the set screw ll being to prevent the spring pressed ratchet bolt N from rotating in the body A; and in case it is desired to cut a left-hand thread, the set screw N is removed and the ratchet bolt N rotated one-half of a revolution, so that the inclined suri'ace 12 on the upper end thereof will face in the opposite direction.

in operation the drawings show the chasers B in their expanded position, b ing maintained in that position by the studs M resting in the slots 6 in the ring E at which time the points of the cam surfaces C restsupon the points of the can:

surfaces B (see Fig. 1), and the points of? the cam surfaces D, on the sleeve D, projecting between the cams C of: the sleeve C". which torces the member B with its inclined under-cut beads B downward against the inner ends of the chasers B. Now, when the chasers have cut threads to the predetermined depth, the tool holder ot the machine into which the shank part E secured, is drawn backwardly, which causes the shank part E to move longitudinally within the body A so as to disengage the studs M from the slots c in the ring E, and the continued rotation of the work pie-e upon the chascrs B will then cause the body A to rotate upon the shank part l5 sutiiciently to cause the lower points of the cams C to move oil of the upper points or the cams 3 when the spring ll, strain upwardly on the shank B causes said s to co-operate to ins antly rotate the body in. upon the shank part E substantially a one-quarter said rotation being stopped. by the s1 ressed ratchet bolt N. which action of e spring H, co-operating with the cams and causes the member B to move upwardly within the body it, which movement causes the chasers B to recede iron. the work piece as described in my afore mentioned Letters Patent.

lt will be noted that during this opera-- tion the shaft B, member B, and sleeve collar D rotate in unison with the body A. while the sleeve C remains at rest with the shank part l5; this rotation of the member B and shaft 3* being caused by the crossllO bar L in the lower part of the member B extending into a pair of the slots at in the body A, thus re-enforcing the under-cut ribs B which also operate in said slots.

It will also be noted that the co-operation of the cam surfaces C and D will cause an upward movement of the member B, if the spring H were eliminated, so that in case said spring II should be broken, the chasers B would recede sufliciently from their work to permit the tap to be withdrawn there from without injury to the finished threads. lVhen the tap is withdrawn from the work, the lever L is grasped by the operator, and by means thereof the body A is rotated in a direction reverse to that in which it had just been rotated by the spring H, which again forces the member B downwardly within the body A and expands the chasers B.

To adjust the expanded diameter of the chasers B the collar F is rotated upon the body A which causes the same to move longitudinally thereon by reason of the screw threads f, this longitudinal movement of the collar F acting against the anti friction bearings F and F and posts 4, adjusts the longitudinal position of the cam sleeve C, which in turn regulates the longitudinal position of the member 13, which causes the under-cut inclined beads B on the lower end of the member B to expand or retract the expanded position of the chasers B as may be desired.

Having thus fully shown and described my invention so as to enable others to utilize the same what I claim as new and desire to secure by Letters Patent is 1. In a collapsible tap, a body member, chasers radially and slidably mounted in one end thereoi, a longitudinally movable means within said body member engaging theinner ends of said chasers, a shank member adapted to rotate within said body member a partial revolution, and a cam sleeve on said longitudinally movable member rotatable with said body member and adapted to impart movement to said longitudinally movable means.

2. In a collapsible tap, a body member, chasers radially and slidably mounted in one end thereof, a longitudinally movable menr ber within said body member engaging the inner ends of said chasers, a sleeve rotatably mounted on said longitudinally movable member, co-acting cams on said longitudinally movable member and said sleeve, a shank member adapted to rotate within said body member. means to cause said sleeve to rotate in unison with said shank member, and means to disengagingly lock said body member and shank member against relative rotation.

3. In a collapsible tap, a-body member having radial ehasers slidably mounted in one end thereof, a longitudinally movable member uon-rotatably mounted in said body member and adapted to transpose its longitudinal movement into radial movement of said chasers, cams at the upper end. thereof, a shaft member extending upward from said cams, a sleeve mounted on said. shaft member, a sleeve-collar non-rotatingly fixed on said shaft member above said sleeve, cams on the lower end of said sleeve collar, cams on each end of said sleeve adapted to co-act with the cams on said longitudinally movable member and said sleeve collar, to impart longitudinal movement to said longitudinally movable member, a shank member ro'tatably and slidably mounted in said body member, means to lock said shank member and said sleeve together in unitary rotatable movement, while permitting relative longitudinal movement of said parts, means to disengagingly lock said body member and said shank member against relative rotative movement, means to adjust the relative longitudinal positions of said sleeve and said shank member, and spring mechanism normally operating in opposition to said cams.

l. In a collapsible tap, a body member, radial chasers slidably mounted in one end thereof, a slrank rotatably and slidably mounted in the opposite end of said body member, a longitudinally movable central member within said body and shank members adapted to control the radial movement of said chaser-s, cam mechanism actuated by relative rotative movement of said body and shank members to control the longitudinal movement of said central member, and interlocking means between said body and shank members adapted to prevent relative rotation and be disengaged by relative longitudinal movement.

5. In a collapsible tap, a body member, radially slidable chasers mounted in one end thereof, a hollow shank rotatably and slidably mounted in the opposite end of said body member, an annular shoulder on said shank within said body member. a collar screwed into the body member above said annular shoulder to prevent the withdrawal, of said shank from said. body, a central longitudinally movable member within said body member adapted to engage said chasers and impart radial movement thereto, means to prevent relative rotation of said central and body members, a sleeve rotatably mounted on said central member, co-acting cams on said sleeve and central member adapted to cause reciprocal longitudinal movement of said central member, means on said sleeve adapted'to prevent relative roative movement thereof with said shank, means to engage the inner end of said screw collar to adjust the longitudinal position of said sleeve with relation to said shank, and means adapted to be disengaged by the ars body

relative longitudinal movement of said member and said shank to interlock members.

6. In a collapsible tap, a body member, radially slidable chasers in one end thereof, a hollow shank slidably and rotatably mounted in the opposite end thereof and having a transverse slot across the inner end thereof, a ring secured. on the lower end of said shank having radial slots in the lower surface thereof, a central longitudinally movable member within said body member and said shank adapted to engage and impart radial movement to said chasers, a rotatable sleeve mounted on said central member, co-acting cams on said sleeve and aid central member adapted to control the longitudinal movement of said central member, arms on said sleeve projecting into said transverse slot, posts secured in said arms and projecting upwardly therefrom, a collar screwed into the upper end of said body member adapted to be engaged by said posts to control. the longitudinal position of said sleeve with relation to said shank, stuns secured in said body member adapted to engage said radial slots in said ring, and a spring in said hollow shank to normally maintain said studs in engagement with said radial slots.

7 In a collapsible tap, a hollow body member, chasers radially slidable in one end ther of, an annular shoulder Within said member,

one or more driving SbllClS secured in said shoulder, a spring pressed ratchet post mounted. in said shoulder, hollow shank rotatably and slidably mounted within the opposite end of said body member and having a transverse slot in the inner end thereof, a collar screwed into said body member around said shank adapted to be adjusted longitudinally therein, a ring secured on the lower end oi? said shank having radial notches in the lower annular surface thereof adapted to receive said driving studs, a central longitudinally movable member within said body member and said hollow shank, a block secured within said hollow shank adjacent to its upper end, a spring secured to said block and to said central member and adapted to move said central member in one direction therein, a sleeve rotatably mounted in said central member, co-acting cams on said central member and said sleeve adapted to move said central member against the action of said spring, arms on said sleeve extending into the transverse slot in said shank, and means on said arms to engage said screw collar whereby the longitudinal position of said sleeve and the central member with relation to said body and shank members may be adjusted by said screw collar.

In testimony whereof I my signature.

RUDOLPH A. BOEHM. 

